Applying temperature-dependent losses to high-fidelity electric motor analysis

Abstract

Turning to hybrid-electric and electric propulsion in the aviation industry brings about a new set of engineering design challenges. There has always been motivation to optimize existing propulsion technologies such as gas-turbine or turbo-prop engines. Electric motors are a more novel technology that has not been fully optimized to date. Engineers need to make geometric design decisions to make these motors as efficient, light, or powerful as possible. To date, there has been limited high-fidelity analysis and optimization performed for propulsive electric motors for aircraft. Previous aircraft motor analysis and optimization have not accounted for the fully coupled nature of the electromagnetic and thermal analyses needed for analysis and optimization. In addition, electromagnetic losses have been considered without regard to temperature. In order to optimize propulsive electric motors for aircraft, a multidisciplinary high-fidelity analysis model in the form of a software tool is needed that accounts for temperature-dependent losses and allows for both one-way and bi-directional electro-thermal coupling. Temperature-dependent loss models are adapted from the literature and applied to a motor model problem. These models provide the interface between the electromagnetic and thermal analyses that allow for both one-way and bi-directional electro-thermal coupling. The high-fidelity one-way and bi-directional electro-thermal coupled results validate the conservation of energy and demonstrate the importance of accounting for temperature in electric motor analyses. Furthermore, it is shown that bi-directional electro-thermal coupling allows for more accurate solutions in both disciplines.